3D Animation Workshop: Lesson 48: Picture Perfect | 2

Lesson 48 - Picture Perfect - Part 3

The reflection of the wood grain of the table top on the bottom of the plate is especially effective. And what seems to be the shadow of the dish on the table surface is in fact a subtle reflection.

These kinds of reflections, however, are already achievable with standard ray tracing in any application. To understand the revolutionary impact of radiosity we have to play with the contribution of diffuse reflection from the walls.

Here's the same scene with the color of the plate changed to a neutral white-gray.

Next we'll change the color of the floor to something much warmer, and re-render.

The subtle differences are astounding. No changes were made in the lighting or the color of the walls. They are still "painted" white. But the new floor color has made them sunny orange by reflection, and this colored light bouncing off the walls also affects the objects in the room. The dish picks up the color cast and the even the table (with its varnished finish) reflects a much warmer tone. This kind of tangible atmosphere is impossible without radiosity underlying the ray tracing.

Now let's turn the light off in the room and rely only on window light. I changed the daytime to 2:00 P.M. (it was 10:00 A.M.) to get some direct sunlight through the window. This has a nice afternoon feel. Notice how much has changed.

It's now clear that the walls are painted white, and that the dish is glazed white. The character of the hardwood table has completely changed, revealing how dark the wood color actually is and how much surface reflection contributes to the impression of finished wood. The window light that still reflects off the corner of the table is now a striking touch. The rectangle of sunlight on the floor adds the feeling that it's warm and sunny outside.

Learning Lightscape is mostly a matter of making experiments just like these and carefully examining the results. One quickly develops a new sensitivity to the miracle of light.